We present photoconductivity data on GaAs quantum wires grown on aV-grooved substrate by flow rate modulation epitaxy. They show that a moderate excitation power density, ∼1W/cm2,allows the observation of the absorption structure of a single GaAs quantum wire embedded in ap-i-ndiode. Furthermore, by increasing the number of active wires inside a diode, the photoconductivity signal is enhanced and additional details of the absorption structure are evidenced. And, finally, a rough quantitative agreement is obtained between the experimental absorption transitions and a simple calculation of the one-dimensional excitonic states using the envelope function approximation. ©1997 American Institute of Physics.